This invention relates to apparatus for producing food products having the appearance of the shelled meat of shellfish, such as shrimp, crab, lobster and abalone, by molding and processing a paste of ground fish meat.
In the past, molds used to produce food products resembling the appearance of the shelled meat of shellfish were used by fitting together two elongated aluminum mold halves which form a series of multiple food product mold cavities, injecting under pressure a raw food paste into the mold, and then heating the mold. Such molds have been provided with hinges along one lengthwise side in order to allow the two mold halves to be opened and closed, and the two unhinged ends of the mold have been secured in order to prevent the mold halves from opening. However, in the past when the molds were filled with the raw food paste, the two mold halves would instantly open a slight amount, thus causing the food product to have an edge around it when it is heated and removed from the mold. The presence of an edge around the food product decreased the value of the product because it is not sufficiently authentic in appearance and thus necessitates a procedure to removed the edge.
Usually either six to eight individual molds are arranged in a frame, or multiple food product mold cavities are formed in a single mold and these are all opened and closed simultaneously. In order to initially prevent the formation of this edge, the number of these molds or cavities can be reduced to three or four, thus reducing the span of the mold which has to be clamped together and increasing the strength provided to resist the internal pressure tending to open the molds; or the speed at which the raw food paste is injected can be reduced in order to prevent the internal pressure from increasing excessively. In either case, however, there is a resulting drop in productivity.
Another measure which might be considered in an effort to prevent the formation of an edge around the food product is to shape the edges of each mold cavity so that they interlock, but this expedient not only would make formation of the molds more complex, an edge might still be formed around the product if there were any gaps in the mold joints.
A design in which tapered parts are provided to hold both sides of the mold when the paste injection nozzles descend during the injection of the raw food paste and thus prevent the opening of the mold is disclosed in the applicants' U.S. patent application Ser. No. 879,984 filed on June 30, 1986. However, as the closure of the mold tended to open between the tapered parts, this design has not been a perfect solution.
Although each of the methods used in the past had advantages of its own, there were also such disadvantages as a complicated construction, reduced productivity, etc. The pressure especially tends to increase when the raw food paste being injected into the mold cavities is highly viscous and lacks fluidity. The pressure working to push open the mold is particularly strong in mold cavities such as those shaped in the form of a shrimp, where the cross-sectional area gradually decreases as the paste is injected. There is also a considerable amount of force caused by the expansion of the food product during heating of the mold. Prior art mechanisms have not been able to deal with these forces.